GFDL CM4 Model

Geophysical Fluid Dynamics Laboratory (GFDL).

The layout of this package includes the following directories:

• src - The source code for the CM4 model
• exec - The build directory with Makefiles for building the model executable
• run - Sample run script

Cloning Instructions

This repository uses git submodules to point to other repositories. Thus, care should be taken when cloning, and updating the source to ensure all source. To obtain all source, use the following git command

git clone --recursive https://github.com/NOAA-GFDL/CM4.git

The --recursive option to git clone instructs git to recursively clone all submodules. In the event the repository was not cloned using the --recursive option, the following step must be taken to obtain all sources:

# From within the CM4 parent directory
git submodule update --init --recursive

Source Code

All model source is contained in the src directory. GFDL tracks code using the git version control system. This package includes a single version of the following GFDL model components. The git hash listed corresponds to the commit hash in the internal GFDL git repository.

Component	Commit Hash
atmos_cubed_sphere	b8b05bf650c0d3293b538bdaceb894ba0fd6910b
atmos_drivers	3be6ed406de2db29766746a69115fd6a47048692
atmos_param	4fe4ca54a0224ef5c4cf9ebf1010d5b869930a3f
atmos_shared	2e9d8b770cdb2d70d8d9264e4b2de24213ae21bd
land_lad2	154bd2b4bf523f3e699de5017679b156242ec13f

The following components are available in the NOAA-GFDL github organization:

• MOM6
• SIS2
• GFDL_atmos_cubed_sphere (as atmos_cubed_sphere)
• icebergs
• ice_param
• ocean_BGC
• coupler
• FMS (as shared)
• mocsy

Building CM4

Containers

The container folder provides example Dockerfiles and Signularity definition files to use to build AM4 containers using either GCC/GFORTAN or Intel oneAPI. There is a script that can be used to build the intel singularity containers, and the first step of this script can be used with the other GFDL climate models.

From source

The exec directory contains Makefiles that can be used to build the CM4 executable. These Makefiles were generated using the Make Makefile (mkmf) program. Included in the exec direcgtory is a sample make template file for the Intel compilers (intel.mk). This make template can be used on any system with a relatively recent version of the Intel compilers, the netCDF 4 library and the MPICH2 MPI library. Included in the intel.mk file are additional settings that can be modified during the build.

To run the default build (-O3 -msse2), go to the exec directory and enter the command

make HDF_INCLUDE=-I/path/to/hdf5/include

Where /path/to/hdf5/include is the path to your HDF5 include folder where hdf5.mod is.

If you would like to change some of the compiler options, there are several different options to add to the make command. For example

make ISA=-xhost REPRO=on

will replace -msse with -xhost and -O3 with -O2. The three options for building are
PROD=on (-O3) Default REPRO=on (-O2)
DEBUG=on (-O0 and other traps)
All of the make line options can be found in the intel.mk file.

To build with GNU compilers, add gcc=on to the make line. The make line options can be found in the gnu.mk file.

Obtaining the input data

The input data required for running the CM4 model can be found on GFDL's data portal .

The file CM4_runDir.tar.gz contains a configured run directory to run a sample experiment of the CM4 model. Included in the tar file is a README.CM4 with more instructions on how to configure the CM4 run directory.

Running CM4

Included in the run directory is a sample run script for reference. To run the CM4 sample experiment, first download the data file mentioned in Obtaining the Input data section. Modify the variables in the configuration section in the sample run script, and then run the script.

The sample data and run script are configured to run on a total of 8127 processors (864 cores 4 threads for the atmosphere and 4671 ocean cores).
To run on a different number of processors, or modify the experiment, refer to the README.CM4 file included in the CM4 data tarball.

Note: The input.nml file (found in the CM4 data tarball) contains Fortran namelists and namelist variables that modify, at run time, the model. To learn more about the settings in the input.nml file, please refer to source code where the namelist/variable are defined.

Model output and Other References

Please refer to the CM4 data and code site for details about where to find model and OBS data used in the papers.

For all analysis figures and pertaining data, please use the CM4 documentation papers as the original reference.

Please direct your questions and feedback to gfdl.climate.model.info@noaa.gov

Disclaimer

The United States Department of Commerce (DOC) GitHub project code is provided on an 'as is' basis and the user assumes responsibility for its use. DOC has relinquished control of the information and no longer has responsibility to protect the integrity, confidentiality, or availability of the information. Any claims against the Department of Commerce stemming from the use of its GitHub project will be governed by all applicable Federal law. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply their endorsement, recommendation or favoring by the Department of Commerce. The Department of Commerce seal and logo, or the seal and logo of a DOC bureau, shall not be used in any manner to imply endorsement of any commercial product or activity by DOC or the United States Government.

This project code is made available through GitHub but is managed by NOAA-GFDL at https://gitlab.gfdl.noaa.gov.